JP2015225457A - Method of creating raw tire model and method of simulating deformation on raw tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of creating a raw tire model capable of reproducing changes in angle and distance of cords of a reinforcement material useful for developing a finished tire.SOLUTION: The method of creating a raw tire model is a method, using a computer 1, for creating a raw tire model 40 modeling a raw tire 2 including a reinforcement material 3 in which plural cords 11 are covered with unvulcanized rubber 12. The method includes: a step S1 to input a reinforcement material model 29 which simulates the reinforcement material 3 on the computer 1. The reinforcement material model input step S1 includes a step to input a cord model 20 which simulates the respective cords 11 using beam elements Fi.

Description

  The present invention relates to a raw tire model creation method and a raw tire deformation simulation method useful for tire development.

  In recent years, various simulation methods for numerically calculating the deformation state of a raw tire in a tire manufacturing process, particularly in a vulcanization process using a computer have been proposed.

  In this type of simulation method, for example, a raw tire model is created by modeling (discretizing) a raw tire with a finite number of elements. The raw tire model includes a reinforcing material model obtained by modeling a reinforcing material such as a carcass ply. The actual reinforcing material has a plurality of cords. For example, a shell element in which the angle of the cord with respect to the tire circumferential direction is defined as rigidity anisotropy is used for the reinforcing material model.

Japanese Patent No. 5297223

  The reinforcement model as described above does not have an independently modeled cord. Therefore, the reinforcing material model has a problem in that changes in the angle and interval of the cord caused by deformation of the reinforcing material cannot be reproduced.

  The present invention has been devised in view of the actual situation as described above. Based on modeling each cord of the reinforcing material with a beam element, the change in the angle and interval of the cord of the reinforcing material is reproduced and finished. The main object is to provide a method for creating a raw tire model useful for tire development and a method for simulating deformation of the raw tire.

  The present invention is a method for creating, using a computer, a raw tire model obtained by modeling a raw tire having a reinforcing material in which a plurality of cords are coated with unvulcanized rubber. A reinforcing material model inputting step of inputting a reinforcing material model obtained by modeling the reinforcing material, and the reinforcing material model inputting step includes a step of inputting a code model obtained by modeling each code with a beam element. And

  In the green tire model creating method according to the present invention, it is preferable that the beam element defines a material property of the cord.

  In the raw tire model creation method according to the present invention, the reinforcing material model input step further includes a step of inputting an unvulcanized rubber model obtained by modeling the unvulcanized rubber with a finite number of elements. Is desirable.

  In the method for producing a green tire model according to the present invention, the cord includes a carcass cord extending between a pair of bead cores, and a belt cord disposed on the outer side in the tire radial direction of the carcass cord and inside the tread portion. Is desirable.

  In the raw tire model creation method according to the present invention, a step of inputting a carcass ply model obtained by modeling a carcass ply having the carcass cord into a finite number of elements to the computer, and the belt cord to the computer. A step of inputting a belt ply model obtained by modeling a belt ply having a finite number of elements, a rubber member including unvulcanized sidewall rubber is modeled by a finite number of elements in the computer, and the carcass ply model A step of setting a casing model integrated with the belt, a step of setting a tread ring model integrated with the belt ply model by modeling unvulcanized tread rubber with a finite number of elements in the computer, The outer surface of the casing model in the radial direction of the tire, and the Setting a boundary condition defining contact with a tire ring inner surface of the dreadling model, and the computer so that the outer surface of the casing model and the inner surface of the tread ring model are in contact with each other. It is desirable to include a step of deforming at least one of the model and the tread ring model.

  The present invention uses the raw tire model according to any one of claims 1 to 5 to evaluate deformation of the raw tire in a vulcanization process using a vulcanization mold and a bladder using the computer. A method for inputting a mold model in which the vulcanization mold is modeled with a finite number of elements to the computer, and a bladder in which the bladder is modeled with a finite number of elements. Inputting a model; setting a boundary condition defining a contact between an outer surface in the tire radial direction of the bladder model and an inner surface in the tire radial direction of the raw tire model in the computer; and Setting a boundary condition defining contact between an outer surface in the tire radial direction of the tire model and an inner surface in the tire radial direction of the mold model; A computer deforming at least one of the bladder model or the raw tire model so that the outer surface of the bladder model and the inner surface of the raw tire model are in contact with each other; and the computer includes the raw tire The method includes a vulcanization simulation step of deforming at least one of the mold model or the raw tire model so that the outer surface of the model contacts the inner surface of the mold model.

In the raw tire deformation simulation method according to the present invention, the vulcanization simulation step includes the step of arranging the mold model outside the raw tire model, and the bladder model and the raw tire model in a tire radial direction. It is desirable to include a step of expanding and deforming outward.

  The raw tire model creation method according to claim 1 includes a reinforcing material model input step of inputting a reinforcing material model obtained by modeling a reinforcing material having a plurality of cords to a computer. The reinforcing material model input step includes a step of inputting a code model obtained by modeling each code with a beam element.

  The beam element representing the code can be deformed independently as the reinforcement model is deformed. For this reason, the deformation | transformation simulation is performed using the raw tire model created with the method of this embodiment, and the change of the angle | corner or space | interval of the cord after a deformation | transformation of a reinforcement can be reproduced.

  In the simulation method according to claim 6, a step of inputting a mold model obtained by modeling a vulcanization mold with a finite number of elements to a computer, a step of inputting a bladder model obtained by modeling a bladder with a finite number of elements, A step of setting boundary conditions defining contact between the outer surface of the bladder model in the radial direction of the tire and the inner surface of the raw tire model in the radial direction of the tire, and the outer surface of the raw tire model in the radial direction of the tire and the tire of the mold model Setting boundary conditions defining contact with the radially inner surface.

  Furthermore, in the simulation method according to claim 6, the computer deforms at least one of the bladder model or the raw tire model so that the outer surface of the bladder model and the inner surface of the raw tire model are in contact with each other, and the raw tire A vulcanization simulation step of deforming at least one of the mold model and the green tire model so that the outer surface of the model is in contact with the inner surface of the mold model is included.

  In such a simulation method according to claim 6, since the deformation of the raw tire model during vulcanization molding can be calculated by bringing the outer surface of the raw tire model into contact with the inner surface of the mold model, The shape of the raw tire can be reproduced. Moreover, in the simulation method according to the sixth aspect, since a tire model having a code model in which each code is modeled by a beam element is used, the deformation of the code during vulcanization can be accurately reproduced.

It is a perspective view of the computer which performs the preparation method of the raw tire of this embodiment, and the deformation | transformation simulation method of a raw tire. It is sectional drawing which shows the raw tire of evaluation object. (A) is a partial perspective view of a carcass ply, (b) is a partial perspective view of a belt ply. It is sectional drawing explaining the shaping | molding method of a green tire. It is sectional drawing explaining the vulcanization | cure process of a green tire. It is a flowchart which shows the specific process sequence of the preparation method of the raw tire of this embodiment. It is a flowchart which shows an example of the process sequence of a reinforcement material model input process. It is a flowchart which shows an example of the process sequence of a carcass ply model input process. It is a disassembled perspective view which shows a part of carcass ply model of this embodiment. It is a flowchart which shows an example of the process sequence of a belt ply model input process. It is a disassembled perspective view which shows a part of belt ply model of this embodiment. It is a flowchart which shows the process sequence of the casing model setting process of this embodiment. It is a fragmentary perspective view of the casing model of this embodiment. It is a flowchart which shows the process sequence of the tread ring model setting process of this embodiment. It is a fragmentary perspective view of the tread ring model of this embodiment. It is a flowchart which shows the process sequence of the shaping process of this embodiment. It is a figure explaining the shaping process of this embodiment. It is a flowchart which shows the process sequence of the simulation method of this embodiment. It is a figure explaining the bladder deformation | transformation process of this embodiment. It is a figure explaining the vulcanization simulation process of this embodiment. It is a flowchart which shows the process sequence of the bladder deformation | transformation process of this embodiment. It is a flowchart which shows the process sequence of the vulcanization simulation process of this embodiment. It is a figure which shows the raw tire model of an Example. It is a figure which shows the raw tire model of a comparative example.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
The raw tire model creation method of the present embodiment (hereinafter sometimes simply referred to as “creation method”) is a method for creating a raw tire model obtained by modeling a raw tire to be evaluated using a computer. is there.

  FIG. 1 shows a computer 1 that executes a creation method of the present embodiment and a raw tire deformation simulation method (hereinafter also referred to simply as “simulation method”). The computer 1 includes a main body 1a, a keyboard 1b, a mouse 1c, and a display device 1d. The main body 1a is provided with an arithmetic processing unit (CPU), a ROM, a working memory, a storage device such as a magnetic disk, and disk drive devices 1a1, 1a2. Note that a processing procedure (program) for executing the creation method and simulation method of the present embodiment is stored in the storage device in advance.

  FIG. 2 is a cross-sectional view showing the raw tire 2 to be evaluated. FIG. 3A is a partial perspective view of the carcass ply. FIG. 3B is a partial perspective view of the belt ply. As shown in FIGS. 2 and 3, the green tire 2 of the present embodiment has a reinforcing material 3 in which a plurality of cords 11 are covered with unvulcanized rubber 12. The reinforcing member 3 of the present embodiment includes a carcass 6 extending from the tread portion 2a through the sidewall portion 2b to the bead core 5 of the bead portion 2c, and a belt disposed outside the carcass 6 in the tire radial direction and inside the tread portion 2a. Layer 7.

  As shown in FIG. 2, the carcass 6 is composed of at least one carcass ply 6 </ b> A in the present embodiment. The carcass ply 6A has a main body portion 6a extending from the tread portion 2a through the sidewall portion 2b to the bead core 5 of the bead portion 2c, and the bead core 5 connected to the main body portion 6a is folded back from the inner side in the tire axial direction. And a folded portion 6b.

  As shown in FIG. 3A, the carcass ply 6A has a carcass cord 6c arranged at an angle θ1 of, for example, 75 to 90 degrees with respect to the tire equator C, and unapplied to cover these carcass cords 6c. And a sulfur rubber (topping rubber) 6d. The carcass cord 6c extends between the pair of bead cores 5 and 5 (shown in FIG. 2).

  As shown in FIG. 2, the belt layer 7 includes at least two belt plies including an inner belt ply 7A and an outer belt ply 7B that are overlapped in the tire radial direction in the present embodiment. Yes.

  As shown in FIG. 3 (b), the belt plies 7A and 7B include belt cords 7c and 7c inclined at an angle θ2 of, for example, 10 to 40 degrees with respect to the tire circumferential direction, and these belt cords 7c. It comprises unvulcanized rubber (topping rubber) 7d, 7d to be coated. The belt cords 7c and 7c of the belt plies 7A and 7B are overlapped with each other so as to cross each other. The belt cords 7c and 7c are arranged on the outer side in the tire radial direction of the carcass cord 6c (shown in FIG. 3A) and inside the tread portion 2a (shown in FIG. 2).

  As shown in FIG. 2, the raw tire 2 includes an unvulcanized tread rubber 4 a disposed on the outer side in the tire radial direction of the belt layer 7, and a sidewall rubber disposed on the outer side in the tire axial direction of the carcass 6. 4b is provided. Further, the raw tire 2 is provided with an inner liner rubber 4c disposed inside the carcass 6 and a bead apex rubber 4d extending from the bead core 5 to the tread rubber 4a side between the main body portion 6a and the folded portion 6b. ing.

  FIG. 4 is a cross-sectional view illustrating a method for forming the raw tire 2. In the molding method of the present embodiment, as in the conventional molding method, first, an unvulcanized inner liner rubber 4c, a carcass ply 6A, a bead core 5, an unvulcanized bead apex are formed on a cylindrical drum (not shown). The rubber 4d and the unvulcanized sidewall rubber 4b are wound. Thereby, the cylindrical casing 13 (indicated by a two-dot chain line) is formed. Next, in the molding method, for example, the unvulcanized tread rubber 4a and the belt plies 7A and 7B are wound around a drum (not shown) having a larger diameter than the drum forming the casing 13. Thereby, the cylindrical tread ring 14 is formed.

  Next, in the molding method of the raw tire 2, the casing 13 is bulged (shaped) in a toroidal shape while the axial distance of the bead cores 5 and 5 is reduced by the bead holding portion 15 that holds the bead cores 5.

  On the outer peripheral surface of the casing 13, the inner peripheral surface of the tread ring 14 that has been waiting in advance in the radial direction is attached. The stitching roller (not shown) is pressed against the outer peripheral surface 14 o of the tread ring 14, so that the outer peripheral surface of the casing 13 and the inner peripheral surface of the tread ring 14 are brought into close contact with each other. Thereby, the green tire 2 shown in FIG. 2 is formed.

  FIG. 5 is a cross-sectional view illustrating a vulcanization process of the raw tire 2. In the vulcanization step, first, the green tire 2 is put into the vulcanization mold 16 as in the conventional tire manufacturing method. Next, the green tire 2 put into the vulcanizing mold 16 is pressed against the molding surface 16 s of the vulcanizing mold 16 and heated by the bladder 17 made of an elastic body. Thus, the raw tire 2 is vulcanized and a tire (not shown) is manufactured.

  FIG. 6 is a flowchart showing a specific processing procedure of the creation method of the present embodiment. In the creation method of the present embodiment, first, a reinforcing material model 29 obtained by modeling the reinforcing material 3 shown in FIG. 2 with a finite number of elements is input to the computer (reinforcing material model input step S1). The reinforcing material model 29 of the present embodiment includes a carcass ply model that models the carcass ply 6A and a belt ply model that models the belt plies 7A and 7B. FIG. 7 is a flowchart showing an example of the processing procedure of the reinforcing material model input step S1.

  In the reinforcing material model input step S1 of the present embodiment, first, a carcass ply model obtained by modeling the carcass ply 6A shown in FIG. 2 with a finite number of elements is input (carcass ply model input step S11). FIG. 8 is a flowchart showing an example of the processing procedure of the carcass ply model input step S11. FIG. 9 is an exploded perspective view showing a part of the carcass ply model of the present embodiment.

  In the carcass ply model input step S11 of the present embodiment, first, a carcass code model 21 (code model 20) obtained by modeling each carcass code 6c (shown in FIG. 3A) with a beam element Fi is input to the computer 1. (Step S111).

  In step S111 of this embodiment, first, design data (for example, CAD data) of the carcass ply 6A (shown in FIG. 4) wound around a drum (not shown) is input to the computer 1. This design data includes numerical data relating to the arrangement of the carcass cord 6c shown in FIG. 3A and the contour of the unvulcanized rubber 6d.

  Next, in step S111, a plurality of beam elements Fi are assigned along the carcass code 6c based on the arrangement of the carcass code 6c (shown in FIG. 3A) of the design data. Thereby, in step S111, the carcass cord model 21 in which the carcass cord 6c of the carcass ply 6A is modeled is set. Such beam element Fi can be easily assigned by using meshing software, for example.

  The beam element Fi is a one-dimensional element defined linearly. The beam element can be handled by a numerical analysis method. As the numerical analysis method, for example, a finite element method, a finite volume method, a difference method, or a boundary element method can be appropriately employed. In this embodiment, the finite element method is adopted. In such a beam element, unlike the two-dimensional shell element and the three-dimensional solid element, it is possible to calculate the longitudinal tension and compression acting on each cord 11 (shown in FIG. 3).

  In the beam element Fi, numerical data including the coordinate value of the node 23 and the material characteristics (for example, density, tensile rigidity, compression rigidity, shear rigidity, bending rigidity, or torsional rigidity) of the carcass cord 6c are defined. Such a carcass code model 21 is stored in a computer.

  Next, in the carcass ply model input step S11, an unvulcanized rubber model obtained by modeling uncured rubber (topping rubber) 6d of the carcass ply 6A with a finite number of elements is input to the computer 1 (step S112). ).

  In step S112 of the present embodiment, unvulcanized rubber 6d (shown in FIG. 3A) can be handled by numerical analysis based on the design data (contour, etc.) of the carcass ply 6A input in step S111. Modeled (discretized) with a finite number of elements Gi. Thereby, in process S112, the unvulcanized rubber model 22 which modeled the unvulcanized rubber 6d of the carcass ply 6A is set. As the numerical analysis method, the same numerical analysis method as the beam element Fi (in this embodiment, the finite element method) is employed.

  In step S112 of the present embodiment, unvulcanized rubber disposed on the inner side in the tire radial direction with respect to the carcass cord 6c and unvulcanized rubber disposed on the outer side in the tire radial direction with respect to the carcass cord 6c. Separately, an unvulcanized rubber model 22 is modeled. Thus, the unvulcanized rubber model 22 includes a first unvulcanized rubber model 22a that models the inner unvulcanized rubber and a second unvulcanized rubber that models the outer unvulcanized rubber. A model 22b is included.

  For example, a three-dimensional solid element is employed as the element Gi. The solid element is preferably a hexahedron element with good accuracy and easy contact surface setting, but it may also be a tetrahedron element suitable for expressing complex shapes, and other 3D solids that can be used with software. Elements may be employed. Each element Gi defines numerical data such as an element number, a node number 24, a coordinate value of the node 24, and material characteristics of the unvulcanized rubber 6d of the carcass ply 6A. Such an unvulcanized rubber model 22 is stored in the computer 1.

  Next, in the carcass ply model input step S11, the carcass cord model 21 (code model 20) and the unvulcanized rubber model 22 are integrated (step S113). In this step S113, the carcass cord model 21 is disposed between the first unvulcanized rubber model 22a and the second unvulcanized rubber model 22b.

  Between the first unvulcanized rubber model 22a and the carcass cord model 21 and between the second unvulcanized rubber model 22b and the carcass cord model 21, a boundary that includes a contact condition for preventing slip-through and a fixed condition is included. A condition is set. The fixing conditions between the carcass cord model 21 and the respective unvulcanized rubber models 22a and 22b are defined based on the actual carcass cord 6c and the unvulcanized rubber 6d shown in FIG. The For this reason, the fixing conditions allow relative movement between the first unvulcanized rubber model 22a and the carcass cord model 21 and between the second unvulcanized rubber model 22b and the carcass cord model 21. is there. Thus, in the carcass ply model input step S11, the carcass ply model 25 (reinforcement material model 29) in which the carcass ply model 21 and the unvulcanized rubber model 22 are integrated to model the carcass ply 6A with high accuracy is obtained. Can be set. Such a carcass ply model 25 is stored in the computer 1.

  As shown in FIG. 7, in the reinforcing material model input step S1, a belt ply model obtained by modeling the belt plies 7A and 7B with a finite number of elements is input (belt ply model input step S12). FIG. 10 is a flowchart showing an example of the processing procedure of the belt ply model input step S12. FIG. 11 is an exploded perspective view showing a part of the belt ply model of the present embodiment.

  In the belt ply model input step S12 of the present embodiment, first, a belt code model 27 (code model 20) obtained by modeling each belt cord 7c (shown in FIG. 3B) with a beam element Fi is input to the computer 1. (Step S121).

  In step S121 of this embodiment, first, design data (for example, CAD data) of belt plies 7A and 7B (shown in FIG. 4) wound around a drum (not shown) is input to the computer 1. This design data includes the arrangement of the belt cords 7c and 7c (shown in FIG. 3B) of the inner belt ply 7A and the outer belt ply 7B, and the unvulcanized rubber 7d (shown in FIG. 3B). Contains numerical data about the contour.

  Next, in step S121, a plurality of beam elements Fi are assigned along the belt cord 7c based on the arrangement of the belt cords 7c of the inner belt ply 7A shown in FIG. Thereby, in step S121, an inner belt cord model 27a obtained by modeling each belt cord 7c of the inner belt ply 7A is set.

  Further, in step S121, a plurality of beam elements Fi are assigned along the belt cord 7c based on the arrangement of the belt cords 7c of the outer belt ply 7B shown in FIG. As a result, in step S121, an outer belt cord model 27b obtained by modeling each belt cord 7c of the outer belt ply 7B is set.

  The beam element Fi is the same as the beam element Fi used in the carcass code model 21 shown in FIG. In the beam element Fi, numerical data including coordinate values of the nodes 23 and material characteristics of the belt cords 7c and 7c are defined. Such belt cord models 27 a and 27 b are stored in the computer 1.

  Next, in the belt ply model input step S12, an unvulcanized rubber model 28 that models the unvulcanized rubber (topping rubber) 7d of the belt plies 7A and 7B shown in FIG. Input (step S122).

  In step S122 of this embodiment, first, based on the design data (contour etc.) of the inner belt ply 7A input in step S121, a finite number of elements Gi that the unvulcanized rubber 7d can handle by numerical analysis. Is modeled (discretized). Thus, in step S122, an inner unvulcanized rubber model 28A that models the unvulcanized rubber 7d of the inner belt ply 7A is set.

  In step S122 of the present embodiment, unvulcanized rubber disposed on the inner side in the tire radial direction with respect to the belt cord 7c of the inner belt ply 7A and unvulcanized rubber disposed on the outer side in the tire radial direction with respect to the belt cord 7c. The inner unvulcanized rubber model 28A is modeled separately from the vulcanized rubber. As a result, the inner unvulcanized rubber model 28A includes the first unvulcanized rubber model 28Aa that models the inner unvulcanized rubber with respect to the belt cord 7c, and the outer unvulcanized rubber model 28A with respect to the belt cord 7c. A second unvulcanized rubber model 28Ab that models a vulcanized rubber is included.

  Furthermore, in step S122, the unvulcanized rubber 7d is modeled with a finite number of elements Gi that can be handled by numerical analysis based on the design data (outline and the like) of the outer belt ply 7B input in step S121 ( Discretized). Thus, in step S122, an outer unvulcanized rubber model 28B that models the unvulcanized rubber 7d of the outer belt ply 7B is set. The outer unvulcanized rubber model 28B of the present embodiment includes a first unvulcanized rubber model 28Ba and a second unvulcanized rubber model 28Bb, similarly to the inner unvulcanized rubber model 28A.

  The element Gi is the same as the element Gi of the unvulcanized rubber model 22 of the carcass ply model 25. The element Gi is defined as numerical data including the coordinate value of the node 24 and the material characteristics of the unvulcanized rubber 7d of the belt plies 7A and 7B shown in FIG. Such an unvulcanized rubber model 28 is stored in the computer 1.

  Next, the belt cord model 27 (code model 20) and the unvulcanized rubber model 28 are integrated (step S123).

  In this step S123, first, the inner belt cord model 27a is disposed between the first unvulcanized rubber model 28Aa and the second unvulcanized rubber model 28Ab of the inner unvulcanized rubber model 28A. Similar to the boundary conditions of the carcass ply model 25 between the first unvulcanized rubber model 28Aa and the inner belt cord model 27a and between the second unvulcanized rubber model 28Ab and the inner belt cord model 27a. A contact condition for preventing slip-through and a boundary condition including a fixed condition are set. Thus, in step S123, the inner belt cord model 27a and the inner unvulcanized rubber model 28A are integrated to set the inner belt ply model 30A (reinforcing material model 29) in which the inner belt ply 7A is modeled with high accuracy. can do.

  Further, in step S123, the outer belt cord model between the first unvulcanized rubber model 28Ba and the second unvulcanized rubber model 28Bb of the outer unvulcanized rubber model 28B, similarly to the inner unvulcanized rubber model 28A. 27b is arranged and a boundary condition is set. Thus, in step S123, an outer belt ply model 30B (reinforcing material model 29) in which the outer belt ply 7B is modeled with high accuracy is set by integrating with the outer belt cord model 27b and the outer unvulcanized rubber model 28B. be able to. These belt ply models 30A and 30B are stored in the computer 1.

  Next, in the creation method of the present embodiment, a casing model integrated with the carcass ply model 25 is set in the computer 1 (casing model setting step S2). FIG. 12 is a flowchart showing a processing procedure of the casing model setting step S2 of the present embodiment. FIG. 13 is a partial perspective view of the casing model of the present embodiment.

  In the casing model setting step S2 of the present embodiment, first, a raw rubber model 31 and a bead core model 32 in which the computer 1 is modeled with the rubber member 4 and the bead core 5 including the unvulcanized sidewall rubber 4b shown in FIG. Is input (step S21). The rubber member 4 of the present embodiment includes an unvulcanized sidewall rubber 4b, an unvulcanized inner liner rubber 4c, and an unvulcanized bead apex rubber 4d.

  In step S21 of the present embodiment, first, design data (for example, CAD data) of an unvulcanized casing 13 (shown in FIG. 4) wound around a drum (not shown) is input to the computer 1. Based on the contours of the unvulcanized sidewall rubber 4b, the unvulcanized inner liner rubber 4c, the unvulcanized bead apex rubber 4d, and the bead core 5 included in the design data, a finite number of elements Gi Is modeled (discretized).

  Thus, in step S21, an unvulcanized sidewall rubber 4b, an unvulcanized inner liner rubber 4c, an unvulcanized bead apex rubber 4d, and a bead core 5 are modeled as a sidewall rubber model 31b and an inner liner rubber model. 31c, a bead apex rubber model 31d, and a bead core model 32 are set. The sidewall rubber model 31b, the inner liner rubber model 31c, the bead apex rubber model 31d, and the bead core model 32 of the present embodiment are modeled by sharing the node 24 of each element Gi. For this reason, the raw rubber model 31 of this embodiment is modeled by integrating the sidewall rubber model 31b, the inner liner rubber model 31c, the bead apex rubber model 31d, and the bead core model 32.

  The element Gi is the same as the element Gi (shown in FIG. 9) of the unvulcanized rubber model 22 of the carcass ply model 25. In this element Gi, numerical data including the coordinate value of the node 24 and the material characteristics of each member are defined. Such raw rubber model 31 and bead core model 32 are stored in computer 1.

  Next, in the casing model setting step S2, the carcass ply model 25 is integrated with the raw rubber model 31 and the bead core model 32 (step S22). In this step S22, the carcass ply model 25 is arranged inside the sidewall rubber model 31b, the inner liner rubber model 31c, the bead apex rubber model 31d and the bead core model 32 based on the design data of the unvulcanized casing 13. The

  Between the side wall rubber model 31b, the inner liner rubber model 31c, the bead apex rubber model 31d and the bead core model 32, and the carcass ply model 25, contact conditions for preventing slipping and boundary conditions including fixed conditions are set. . Thus, in step S22, a cylindrical casing model 36 in which the sidewall rubber model 31b, the inner liner rubber model 31c, the bead apex rubber model 31d, the bead core model 32, and the carcass ply model 25 are integrated can be set. it can. Such a casing model 36 is stored in the computer 1.

  Next, in the creation method of this embodiment, the unvulcanized tread rubber 4a is modeled in the computer 1 and a tread ring model integrated with the belt ply models 30A and 30B is set (tread ring model setting step). S3). FIG. 14 is a flowchart showing a processing procedure of the tread ring model setting step S3 of the present embodiment. FIG. 15 is a partial perspective view of the tread ring model of the present embodiment.

  In step S3 of this embodiment, first, a tread rubber model 31a obtained by modeling an unvulcanized tread rubber 4a (shown in FIG. 4) is input to the computer 1 (step S31). In step S31 of this embodiment, design data (for example, CAD data) of the unvulcanized tread ring 14 (shown in FIG. 4) wound around a drum (not shown) is input to the computer 1. Based on the contour of the unvulcanized tread rubber 4a included in the design data, modeling (discretization) is performed with a finite number of elements Gi. Thereby, in process S31, tread rubber model 31a which modeled unvulcanized tread rubber 4a is set up.

  The element Gi is the same as the element Gi (shown in FIG. 9) of the unvulcanized rubber model 22 of the carcass ply model 25. In this element Gi, numerical data including the coordinate value of the node 24 and the material characteristics of the unvulcanized tread rubber 4a are defined. Such a tread rubber model 31 a is stored in the computer 1.

  Next, in the tread ring model setting step S3, the tread rubber model 31a and the belt ply models 30A and 30B are integrated (step S32). In step S32 of the present embodiment, the outer surface in the radial direction of the outer belt ply model 30B is disposed on the inner surface in the radial direction of the tread rubber model 31a. Further, the radially outer surface of the inner belt ply model 30A is disposed on the radially inner surface of the outer belt ply model 30B.

  Boundary conditions including slipping prevention contact conditions and fixing conditions are set between the tread rubber model 31a and the outer belt ply model 30B and between the outer belt ply model 30B and the inner belt ply model 30A. . Thereby, in process S32, cylindrical tread ring model 39 which unified tread rubber model 31a and belt ply models 30A and 30B can be set up. Such a tread ring model 39 is stored in the computer 1.

  Next, in the creation method of the present embodiment, the boundary condition defining the contact between the outer surface 36o in the tire radial direction of the casing model 36 and the inner surface 39i in the tire radial direction of the tread ring model 39 is set in the computer 1. (Step S4). Thereby, even if the outer surface 36o of the casing model 36 and the inner surface 39i of the tread ring model 39 are in contact with each other, they can be prevented from slipping through each other. Such boundary conditions are stored in the computer 1.

  Next, in the creation method of the present embodiment, the computer 1 brings the outer surface 36o of the casing model 36 into contact with the inner surface 39i of the tread ring model 39 (shaping step S5). FIG. 16 is a flowchart showing the processing procedure of the shaping step S5 of the present embodiment. FIG. 17 is a diagram illustrating the shaping step S5 of the present embodiment.

  In the shaping step S5 of the present embodiment, first, the tread ring model 39 is disposed outside the casing model 36 (step S51). The radial positions of the tread ring model 39 and the casing model 36 are based on the radial positions of the actual tread ring 14 and the casing 13 (shown by a two-dot chain line) before bulging shown in FIG. Is set.

  Next, in the shaping step S5 of the present embodiment, the computer performs a deformation calculation that causes the casing model 36 to bulge outward in the radial direction (step S52). In this step S52, first, an evenly distributed load w1 is defined on the inner surface 36i of the casing model 36. This equally distributed load w1 corresponds to the pressure of the high-pressure air that causes the casing 13 shown in FIG.

  Further, in step S52, deformation calculation for reducing the distance W1 in the tire axial direction of the bead portions 36b and 36b of the casing model 36 is performed. This distance W1 is set based on the distance in the tire axial direction of the bead portions 13b and 13b of the bulged casing 13 shown in FIG. Thereby, in process S52, the deformation calculation which bulges the casing model 36 to a radial direction outer side can be implemented. By the expansion of the casing model 36, the outer surface 36o of the casing model 36 and the inner surface 39i of the tread ring model 39 can be brought into contact with each other.

  The deformation calculation of the casing model 36, the tread ring model 39, and the like is performed for a minute time (unit time Tx (x = 0, 1) based on the shape and material characteristics of each element Fi, Gi (shown in FIGS. 13 and 15). , ...)) is performed every time. Such deformation calculation can be performed using commercially available finite element analysis application software such as LS-DYNA manufactured by JSOL, for example.

  Next, in the shaping step S5, after the outer surface 36o of the casing model 36 and the inner surface 39i of the tread ring model 39 are in contact, the tread ring model 39 is deformed to the casing model 36 side (step S53). In this step S53, an evenly distributed load w2 is defined on the outer surface 39o of the tread ring model 39. The equally distributed load w2 is set based on the pressure of a stitching roller (not shown) that presses the outer peripheral surface 14o of the tread ring 14 shown in FIG. Thereby, in step S53, the deformation calculation of the tread ring model 39 can be performed so that the inner surface 39i of the tread ring model 39 is along the outer surface 36o of the casing model 36.

  Next, in the shaping step S5, boundary conditions for preventing relative movement between the outer surface 36o of the casing model 36 and the inner surface 39i of the tread ring model 39 are set (step S54). Accordingly, in the shaping step S5, the casing model 36 and the tread ring model 39 can be integrated without considering sharing of the nodes 23 and 24 of the elements Fi and Gi shown in FIGS. 9 and 11. .

  Next, in the shaping step S5, the definitions of the equally distributed loads w1, w2 of the casing model 36 and the tread ring model 39 are deleted (step S55). Thereby, in shaping process S5, the raw tire model 40 which modeled the raw tire 2 shown in FIG. 1 can be set. Such a raw tire model 40 is stored in the computer 1.

  In the shaping step S5, the carcass ply model 25 (shown in FIG. 9) and the belt ply models 30A and 30B (shown in FIG. 11) are also deformed by the deformation of the casing model 36 and the tread ring model 39. The carcass cord model 21 and the belt cord models 27a and 27b of the present embodiment are modeled by beam elements Fi, respectively. For this reason, the carcass cord model 21 and the belt cord models 27a and 27b can be independently deformed, unlike a conventional model modeled by a two-dimensional shell element or the like. Therefore, the raw tire model 40 can reproduce the change in the angle or interval of the cord 11 (shown in FIG. 3) accompanying the deformation of the reinforcing material 3 at the time of forming the raw tire.

  In the shaping step S5 of the present embodiment, an example in which both the casing model 36 and the tread ring model 39 are deformed is illustrated, but the present invention is not limited to this. For example, in step S52, when the outline of the tread ring model 39 matches the outline of the tread ring 14 of the raw tire 2 shown in FIG. 2, only the casing model 36 may be deformed. Further, when the contour of the casing model 36 is matched in advance with the contour of the casing 13 of the raw tire 2, only the tread ring model 39 may be deformed. Thereby, in shaping process S5, calculation time can be shortened.

  Next, a simulation method using the raw tire model 40 will be described. The simulation method of the present embodiment is a method for evaluating the deformation of the raw tire 2 in the vulcanization process using the vulcanization mold 16 and the bladder 17 shown in FIG. FIG. 18 is a flowchart showing a processing procedure of the simulation method of the present embodiment. FIG. 19 is a diagram illustrating a bladder deformation process of the present embodiment. FIG. 20 is a diagram illustrating a vulcanization simulation process of the present embodiment.

  In the simulation method of the present embodiment, first, a mold model 43 obtained by modeling the vulcanization mold 16 shown in FIG. 5 with a finite number of elements Gi (not shown) is input to the computer 1 (step S6). . As shown in FIG. 20, the mold model 43 of this embodiment includes a pair of side mold models 44, 44, a tread mold model 45, an upper ring model 46, and a pair of bladder holding models 47, 47. It is configured to include. Each model 44 thru | or 47 of this embodiment is set to the thin plate shape extended in a tire peripheral direction, and is defined so that decomposition | disassembly is possible. Such a mold model 43 is set based on, for example, design data including the contour of the molding surface 16 s of the vulcanizing mold 16.

  In the pair of side molding models 44, 44, a side wall molding surface 44s for molding the side wall portion 40b of the raw tire model 40 and a bead molding surface 44t for molding the bead portion 40c are set. In the tread mold model 45, a tread molding surface 45s for molding the tread portion 40a of the raw tire model 40 is set. The upper ring model 46 is provided with a bladder contact surface 46s on which a part of an outer surface 50o of a bladder model 50 described later is contacted. The pair of bladder holding models 47, 47 has a bladder holding surface 47s with which a part of the inner surface 50i of the bladder model 50 abuts. In the mold model 43, the molding surfaces 44s, 44t, and 45s can be made continuous by assembling the models 44, 45, 46, and 47, respectively. Thereby, the molding surface 16s (shown in FIG. 5) of the vulcanization mold 16 is reproduced on the inner surface 43i of the mold model 43.

  As the element Gi (not shown), a solid element is adopted as in the element Gi (shown in FIG. 9) of the unvulcanized rubber model 22 of the carcass ply model 25. In this element Gi, for example, numerical data including coordinate values of nodes (not shown) and material characteristics of the vulcanization mold 16 (shown in FIG. 5) are defined. Such a mold model 43 is stored in the computer 1.

  Next, in the simulation method of the present embodiment, a bladder model 50 obtained by modeling the bladder 17 shown in FIG. 5 with a finite number of elements is input to the computer 1 (step S7). In step S7 of the present embodiment, the bladder 17 is modeled (discretized) with a finite number of elements Gi (not shown) that can be handled by a numerical analysis method based on the design data (contour, etc.) of the bladder 17.

  As the element Gi (not shown), a solid element is adopted as in the element Gi (shown in FIG. 9) of the unvulcanized rubber model 22 of the carcass ply model 25. In this element Gi, for example, numerical data including the coordinate value of the node 24 and the material property of the bladder 17 are defined. Such a bladder model 50 is stored in the computer 1.

  Next, in the simulation method of the present embodiment, as shown in FIG. 19, the computer 1 defines the contact between the radial outer surface 50 o of the bladder model 50 and the radial inner surface 40 i of the raw tire model 40. A boundary condition is set (step S8). Thereby, even if the outer surface 50o of the bladder model 50 and the inner surface 40i of the raw tire model 40 come into contact with each other, they can be prevented from slipping through each other. Such boundary conditions are stored in the computer 1.

  Next, in the simulation method of the present embodiment, as shown in FIG. 20, the computer 1 is brought into contact with the outer surface 40 o in the tire radial direction of the raw tire model 40 and the inner surface 43 i in the tire radial direction of the mold model 43. Is defined (step S9). Thereby, even if the outer surface 40o of the raw tire model 40 and the inner surface 43i of the mold model 43 come into contact with each other, it is possible to prevent slipping through each other. Such boundary conditions are stored in the computer 1.

  Next, in the simulation method of the present embodiment, as shown in FIG. 9, the computer 1 brings the outer surface 50 o of the bladder model 50 into contact with the inner surface 40 i of the raw tire model 40 (bladder deformation step S <b> 10). FIG. 21 is a flowchart showing the processing procedure of the bladder deformation step S10 of the present embodiment.

  In the bladder deforming step S10 of the present embodiment, first, the mold model 43 is caused to grip the end 50t of the bladder model 50 (step S41). In this step S41, first, the bladder model 50 is disposed inside the pair of side mold models 44, 44 in the tire axial direction. Next, the upper ring model 46 is disposed on the outer surface 50 o of the bladder model 50. A pair of bladder holding models 47, 47 are arranged on the inner surface 50 i of the bladder model 50. Thus, the end portions 50t and 50t of the bladder model 50 are gripped by the side mold model 44, the upper ring model 46, and the pair of bladder holding models 47 and 47.

  Next, in the bladder deformation step S10, the raw tire model 40 is disposed outside the bladder model 50 in the radial direction (step S42). The raw tire model 40 is arranged on the inner side in the tire axial direction than the pair of side mold models 44 and 44.

  Next, in the bladder deformation step S10, an evenly distributed load w3 is defined on the radially inner surface 50i of the bladder model 50 (step S43). This equally distributed load w3 corresponds to the pressure of the high-pressure air that causes the bladder 17 shown in FIG. Thereby, in process S43, the deformation calculation which bulges the bladder model 50 to a radial direction outer side can be implemented. Due to the swelling of the bladder model 50, the outer surface 50o of the bladder model 50 and the inner surface 50i of the raw tire model 40 can be brought into contact with each other.

  In the bladder deformation step S10 of the present embodiment, the bladder model 50 is deformed and the outer surface 50o of the bladder model 50 and the inner surface 40i of the raw tire model 40 are brought into contact with each other. However, the present invention is not limited to this. is not. For example, only the raw tire model 40 or both the raw tire model 40 and the bladder model 50 may be deformed so that the outer surface 50o of the bladder model 50 and the inner surface 40i of the raw tire model 40 are brought into contact with each other.

  Next, in the simulation method of the present embodiment, the computer 1 brings the outer surface 40o of the raw tire model 40 into contact with the inner surface 43i of the mold model 43 (vulcanization simulation step S20). FIG. 22 is a flowchart showing the processing procedure of the vulcanization simulation step S20 of the present embodiment.

  In the vulcanization simulation step S20 of the present embodiment, first, the mold model 43 is arranged outside the raw tire model 40 in the radial direction (step S61). In this step S61, as shown in FIGS. 19 and 20, the upper side mold model 44 and the tread mold model 45 are arranged outside the raw tire model 40. At this time, the upper side mold model 44 is connected to the upper ring model 46 by pressing the bladder model 50 and the raw tire model 40 bulging outward in the tire axial direction toward the inner side (lower side in the drawing). Thereby, the distance of the tire axial direction of the bead parts 40c and 40c of the raw tire model 40 is reduced.

  Next, in the vulcanization simulation step S20, the bladder model 50 and the raw tire model 40 are bulged outwardly (expanded and deformed) based on the evenly distributed load w3 defined on the inner surface 50i of the bladder model 50 (step). S62). Due to the bulging of the raw tire model 40, the outer surface 40o of the raw tire model 40 and the inner surface 43i of the mold model 43 can be brought into contact with each other in step S62. The raw tire model 40 is pressed against the inner surface 43 i of the mold model 43 by the evenly distributed load w <b> 3 of the bladder model 50. For this reason, in the vulcanization simulation step S20, since the deformation state of the raw tire 2 (shown in FIG. 5) during vulcanization molding can be calculated, the shape of the raw tire 2 during vulcanization can be accurately reproduced. Can do.

  Further, in the bladder deformation step S10 and the vulcanization simulation step S20, the carcass ply model 25 and the belt ply models 30A and 30B are deformed by the deformation of the casing model 36 and the tread ring model 39. The carcass cord model 21 (shown in FIG. 9) and the belt cord models 27a and 27b (shown in FIG. 11) of the present embodiment are modeled by beam elements Fi, respectively. For this reason, the carcass cord model 21 and the belt cord models 27a and 27b can be independently deformed, unlike a conventional model modeled by a two-dimensional shell element or the like. Therefore, the raw tire model 40 can accurately reproduce the change in the angle or interval of the cord 11 (shown in FIG. 3) accompanying the deformation of the reinforcing material 3 during vulcanization.

  Next, in the simulation method of this embodiment, it is determined whether or not the deformation state of the raw tire model 40 is good (step S30). In this step S30, when it is determined that the deformation state of the raw tire model 40 is good, the raw tire 2 is manufactured based on the raw tire model 40 (step S40). On the other hand, when it is determined that the deformation state of the raw tire model 40 is defective, the design factor of the raw tire 2 is changed (step S50), and the step S60 for creating the raw tire model 40 (S1 to S1 shown in FIG. 6). S5) and the simulation method (S6 to S30) are performed again. As described above, in the simulation method of the present embodiment, the design factor of the raw tire model 40 is changed until the deformation state of the raw tire model 40 becomes good, so that a tire with excellent molding accuracy can be efficiently designed. it can.

  As mentioned above, although especially preferable embodiment of this invention was explained in full detail, this invention is not limited to embodiment of illustration, It can deform | transform and implement in a various aspect.

  According to the processing procedure shown in FIG. 6, a carcass cord model and a belt cord model obtained by modeling a carcass cord and a belt cord with beam elements were set, and a raw tire model was created (Example). For comparison, a raw tire model in which a carcass ply model including a shell element in which the rigidity anisotropy of the cord is defined and a belt ply model are set was created (comparative example). According to the processing procedure shown in FIG. 18, deformation calculation of the raw tire model of the example and the raw tire model of the comparative example was performed, and the deformation state of the raw tire during vulcanization molding was evaluated. The common specifications are as follows.

Tire size: 195 / 65R15
Simulation software: LS-DYNA made by JSOL

  In this test, the shape of the raw tire model of the example and the shape of the raw tire model of the comparative example were compared immediately before the vulcanization simulation process. FIG. 23 shows a green tire model of an example immediately before the vulcanization simulation process. FIG. 24 shows a green tire model of a comparative example immediately before the vulcanization simulation process.

  As a result of the test, the raw tire model of the example was calculated to have a shape that naturally swelled in the same manner as an actual raw tire. This shape approximates the shape of an actual green tire. On the other hand, in the raw tire model of the comparative example, the tread portion was recessed inward in the radial direction and the sidewall portion protruded outward in the axial direction as compared with the raw tire model of the example. Therefore, it was confirmed that the green tire model of the example can approximate the shape of the actual green tire as compared with the green tire model of the comparative example.

3 Reinforcing material 11 Code 12 Unvulcanized rubber 20 Code model 29 Reinforcing material model 40 Raw tire model Fi Beam element

Claims (7)

A method for creating a raw tire model using a computer by modeling a raw tire having a reinforcing material in which a plurality of cords are coated with unvulcanized rubber,
The computer includes a reinforcing material model input step of inputting a reinforcing material model obtained by modeling the reinforcing material,
The raw tire model creation method, wherein the reinforcing material model input step includes a step of inputting a code model obtained by modeling each of the cords with a beam element.   The raw beam model creating method according to claim 1, wherein a material characteristic of the cord is defined for the beam element.   The raw tire model creation method according to claim 1, wherein the reinforcing material model input step further includes a step of inputting an unvulcanized rubber model obtained by modeling the unvulcanized rubber with a finite number of elements. The cord includes a carcass cord extending between a pair of bead cores,
The method for producing a raw tire model according to any one of claims 1 to 3, further comprising: a belt cord disposed outside the carcass cord in the tire radial direction and inside the tread portion. Inputting to the computer a carcass ply model obtained by modeling the carcass ply having the carcass code with a finite number of elements;
Inputting to the computer a belt ply model obtained by modeling the belt ply having the belt cord with a finite number of elements;
Modeling a rubber member including unvulcanized sidewall rubber in the computer with a finite number of elements, and setting a casing model integrated with the carcass ply model,
Modeling the unvulcanized tread rubber with a finite number of elements in the computer, and setting a tread ring model integrated with the belt ply model;
Setting boundary conditions defining contact between the outer surface of the casing model in the tire radial direction and the inner surface of the tread ring model in the tire radial direction in the computer; and the computer includes the outer surface of the casing model The method for producing a raw tire model according to claim 4, further comprising a step of deforming at least one of the casing model or the tread ring model so that the inner surface of the tread ring model contacts the inner surface. A simulation method for evaluating deformation of the raw tire in a vulcanization process using a vulcanization mold and a bladder using the green tire model according to any one of claims 1 to 5, using the computer. Because
Inputting to the computer a mold model obtained by modeling the vulcanization mold with a finite number of elements;
Inputting a bladder model obtained by modeling the bladder with a finite number of elements to the computer;
Setting boundary conditions defining contact between the outer surface of the bladder model in the tire radial direction and the inner surface of the raw tire model in the tire radial direction on the computer;
Setting boundary conditions defining contact between an outer surface in the tire radial direction of the green tire model and an inner surface in the tire radial direction of the mold model in the computer;
The step of deforming at least one of the bladder model or the raw tire model so that the outer surface of the bladder model and the inner surface of the raw tire model are in contact with each other; and A raw tire deformation simulation comprising a vulcanization simulation step of deforming at least one of the mold model or the raw tire model so that the outer surface of the model contacts the inner surface of the mold model Method. The vulcanization simulation step includes a step of arranging the mold model outside the raw tire model, and a step of expanding and deforming the bladder model and the raw tire model outward in a tire radial direction. Raw tire deformation simulation method.

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